Method of continuous internal broaching



, E. H. H. GRAF ETAL 3,260,163

July 12, 1966' I METHOD OF CONTINUOUS INTERNAL BROACHING Original Filed Aug. 30, 1963 14 Sheets-Sheet l INVENTORS swwmwl N NH Q 4 TOP/V5 Y thaw/909.624; & Z AL Bari J/PA/Vflfll L I July 12, 1966 E. H. H. GRAF ETAL 3,260,163

METHOD OF CONTINUOUS INTERNAL BROACHING Original Filed Aug. 50, 1963 14 Sheets-Sheet INVENTORS July 12, 1966 E. H. H. GRAF ETAL METHOD OF CONTINUOUS INTERNAL BROACHING l4 Sheets-Sheet 5 Original Filed Aug. 30, 1963 L L y m m TA 2 NR4 0 W6? .7 m J g 5 WW fmf 5 Jul 12, 1966 E. H RAF I- 3,260,163

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14 Sheets-Sheet 5 INVENTORS fen 557.4%. GA /2F 2E 147' IQ/VEY July 1966 E. H. H. GRAF ETAL- METHOD OF CONTINUOUS INTERNAL BROACHING Original Filed Aug. 50, 1963 14 Sheets-Sheet 6 y 12, 1966 E. H. H. GRAF ETAL 3,260,163

METHOD OF CONTINUOUS INTERNAL BROACHING Original Filed Aug. 50, 1963 14 Sheets-Sheet v INVENTORS [Ml 576. 6. 6/9/11 54 241. 515 7 5 J/PxM OA L .4

c 14770 NE) July 12, 1966 a. H. H. GRAF ETAL 3,260,163

METHOD OF CONTINUOUS INTERNAL BROACHING 14 Sheets-Sheet 8 Original Filed Aug. 50, 1963 INVENTOR.

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METHOD OF CONTINUOUS INTERNAL BROACHING Original F'il ed Aug. 50, 1963 Y 14 Sheets-Sheet 9 INVENTORS fat 557%? 6/64, 6% E J5 94455275 J/QA/w/JLL July 12, 1966 E. H. H. GRAF ETAL METHOD OF CONTINUOUS INTERNAL BROACHING 14 Sheets-Sheet 10 Original Filed Aug. 50, 1963 I? 3w A INVENTORS fRMfST/Y A. GPA F 54 47 O/QIV'Y July 12, 1966 E. H. H. GRAF ETAL I METHOD OF CONTINUOUS INTERNAL BROACHING Original Filed Aug. 50, 1963 14 Sheets-Sheet 11 L m m M w N o 0 F m m NQ m m N m F \n 6% 1 II LIIIIII mflJ A IHH I I H IHHH IHHHHHH IILIIIIII T. I: TEL I QQNN J 6% 7 I l I l I I I l I I I I l I I III 5 k J II f M w N3 m MUI I I" I. I Il I II I I I i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I l 4 I \I. I I I I I I I I l I y 12, 1966 v E. H. H. GRAF ETAL 3,260,163

METHOD OF CONTINUOUS INTERNAL BROACHING Original Filed Aug. 50, 1963 14 Sheets-Sheet 12 L &L r w M w mm? P v/uP W WW mm M 4? in? V:-///

July 12, 1966 E. H. H. GRAF ETAL 3,260,163

METHOD OF CONTINUOUS INTERNAL BROACHING Original Filed Aug. 30, 1963 14 Sheets-Sheet 13 ,INVENTORS fk/vfsrfl/i 6m F & BYAL 5527i JP/M DALL July 12, 1966 GRAF ETAL 3,260,163

METHOD OF CONTINUOUS INTERNAL BROACHING Original Filed Aug. 30, 1963 14 Sheets-Sheet 14 United States Patent Office 3,260,163 Patented July 12, 1966 3,260,163 METHOD OF CONTINUOUS INTERNAL BROACH'ING Ernest H. H. Graf, Birmingham, Mich., and Albert E. J. Randall, Studley, England, assignors of one-half each to The Detroit Breach & Machine Company, Rochester, Mich., a corporation of Michigan, and B.S.A. Tools Limited, Birmingham, England Original application Aug. 30, 1963, Ser. No. 305,614, now Patent No. 3,185,039, dated May 25, 1965. Divided and this application Mar. 22, 1965, Ser. No. 441,581

- 7 Claims. (Cl. 90-64) This invention relates to an improved method of continuous internal breaching to perform rapidly and accurately internal breaching operations, and is a division of an application of Ernest H. H. Graf and Albert E. J. Randall, Ser. No. 305,614, filed August 30, 1963, new Patent No. 3,185,039, dated May 25, 1965.

In the prior art there have been numerous continuous external breaching methods and machines for performing external breaching operations on work pieces carried by the said work holders traveling along a longitudinal way under breaches fixed in a breach tunnel disposed over the way.

Such methods are employed for the external broaching of certain types of work and are highly efiicient and readily accommodate themselves to combinations of hand, semi-automatic and automatic work loading and unload ing, but none were capable of performing rapidly and accurately continuous internal breaching.

With the foregoing in view, it is the primary object of this invention to provide an improved method of continuous internal breaching which will perform efficiently and efiectively many internal breaching operations.

Another object of this invention is to provide an improved method of continuous internal breaching comprising breach holding and handling steps wherein the breach is releasably supported at least at two spaced intervals at opposite ends thereof, and then sequentially released as apertured work pieces are telescoped onto and guided along the breach parallel to the longitudinal axis thereof.

A further object of the invention is to provide a method of continuous internal breaching of apertured work comprising supporting and holding the breach at spaced intervals at each end thereof, telescoping said apertured work onto and moving it along a path parallel to the longitudinal center of said breach, releasing the breach and removing the supports therefrom and reengaging and resupporting the said breach sequentially at each point of support as the work moves onto the breach at the lead end thereof and from the breach at the tail end thereof, all while always supporting and holding said breach simultaneously at at least one point of support at each end thereof.

A further object of the invention is to provide a method of internal breaching in a breaching machine wherein apertured work to be breached is carried in work holders along ways comprising engaging and supporting a breach parallel to and above said ways at spaced intervals at each end of the breach at an elevation to permit said apertured work to be telescoped thereon, moving said work along said breach while alternately releasing and reengaging said breach at each point of support before and after said work passes each such point of support.

Another object of the invention is to proivde an improved method ef continuous internal breaching comprising holding and supporting a breach at two spaced intervals at each end thereof, and releasing them sequentially a apertured work is forcibly telescoped ever said breach and along the longitudinal axis thereof.

Still another object of the invention is to provide a method of internal breaching as aforesaid including main-' taining the breach in tension during the sequential releasing and holding of said breach in its breaching posi tion.

Other objects of the invention will become apparent by reference to the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a top plan view of a continuous internal breaching machine of a type employable to carry out and illustrate the method of the invention.

FIG. 2 is a longitudinal sectional view taken substantially on the line 22 of FIG. 1.

FIG. 3 is an enlarged fragmentary top plan view taken on the line 3--3 of FIG. 2 of a work holder carried by an endless chain as it approaches the breaching tunnel showing the release and hammer cams carried by the work holder.

FIG. 4 is an enlarged fragmentary vertical sectional view taken on the line 4-4 of FIG. 2.

FIG. 5 is an enlarged fragmentary horizontal sectional view taken on the line 5-5 of FIG. 2 showing the breach holder jaw actuating cams at the lead end of the breach.

FIG. 6 is a vertical sectional view taken on the line 6-6 of FIG. 5.

FIG. 7 is an enlarged vertical sectional view taken on the line 77 of FIG. 2 between the 1st and 2nd pairs of breach holder jaws at the lead end of the breach, the second pair of breach holder jaws being shown in their OPEN position.

FIG. 8 is an enlarged fragmentary plan view taken on the line 88 of FIG. 2 at the rear end of the breaching tunnel showing the 3rd pair of breach holders CLOSED with the 4th pair of breach holders OPEN.

FIG. 9 is a more or less diagrammatic view showing a breach held by the 1st and 3rd pair of breach holder jaws in their CLOSED position while the 2nd and 4th pair are retracted to their OPEN position.

FIG. 10 is a sectional view taken on the line 1010 of FIG. 9. v

FIG. 11 is a sectional view taken on the line 11-11 of FIG. 9.

FIG. 12 is an enlarged plan view at the rear end of the breaching tunnel similar to FIG. 8 showing an alternate construction of the 3rd and 4th pair of breach holder jaws employed to tension the breach.

FIG. 13 is a further enlarged fragmentary view of the 3rd pair of breach holder jaws showing a preferableform of complimentary cam surfaces between the said jaws and the breach shank, the 4th pair ofbroach holder jaws being like and similar.

FIG. 14 is a more or less diagrammatic view showing a breach held by the 1st and 3rd pairs of breach holder jaws in their CLOSED position while the 2nd and 4th pair are retracted, the 3rd and 4th pair of breach holder jaws each having complementary cam formations between the said jaws and the breach shank employed to tension the breach.

FIG. 15 is a sectional view taken on the line 1515 of FIG. 14.

FIG. 16 is a sectional view taken on the line 1616 of FIG. 14.

FIG. 17 is an enlarged plan view at the rear end of the breaching tunnel showing an alternate construction employing a means hydraulically tension the breach using breach jaw and breach formations as in the embodiment of the invention disclosed in FIGS. 1-1l inclusive, both the 3rd and 4th pairs of breach holder jaws being mounted on a single slide.

FIG. 18 is a longitudinal sectional view taken on the line 18-18 of FIG. 17.

FIG. 19 is a cross sectional view taken on the line 19-19 of FIG. 17.

FIG. 20 is a more or less diagrammatic view showing the broach of the embodiment of the invention disclosed in FIGS. 17, 18 and 19 held by the 1st and 3rd pairs of broach holder jaws while the 2nd and 4th pairs are retracted.

FIG. 21 is a sectional view taken on the 'line 2121 of FIG. 20.

FIG. 22 is an enlarged plan view at the rear end of the broaching tunnel showing a further alternate construction employing still another means for tensioning the bnoach wherein the 3rd and 4th pairs of broach holder jaws are each mounted on a separate slide.

FIG. 23 is a longitudinal sectional view taken on the line 2323 of FIG. 22.

FIG. 24 is a horizontal sectional view through the broaching tunnel taken on the line 2424 of FIG. 26 showing hydraulic means for closing and retracting broach holder jaws alternate to the mechanical means employed to operate the broach holder jaws disclosed in the embodiment of the invention shown in FIGS. 1-11 inclusive. FIG. 25 is a vertical sectional view taken on the line 25-25 of FIG. 26.

FIG. 26 is a fragmentary locator side elevational view of the broaching tunnel taken on the lin 2626 of FIG. 24.

Referring now to the drawings wherein like reference characters refer to like and corresponding parts throughout the seveal views, a continuous internal broaching machine illustrating but one means for carrying out the method of continuous internal broaching of the invention disclosed in FIGS. 1-l1 inclusive comprises, in general, a machine frame 11 supporting a longitudinally disposed chain conveyor 12 consisting of a pair of end sprockets 13 mounted on transverse shafts 14 and a pair of laterally spaced roller type chains 15. The said conveyor 12 is driven by convetinonal conveyor drive means, not shown. The laterally spaced conveyor chains 15 carry work holders 16 fixed thereto at intervals therealong. On the machine frame 11 is a pair of longitudinal upper ways 17 which guide and support the upper flight of work holders 16 carried by the conveyor chain 15 between the sprockets 13, while the lower flight of the said work holders 16 is guided and supported on longitudinal lower ways 18.

Above the upper ways 17 is a broach tunnel 20 which houses broach handling mechanism and work holder cam mechanism. The broach handling mechanism sequentially engages and 'disengages a broach B as the work W is carried by work holders 16 along the upper longitudinal ways. The said broach handling mechanism includes a plurality of pairs of broach holder jaws, preferably four pairs, which open and close to permit the work W to be telescoped over, he moved along and removed from the broach B whereby to perm-it an internal broaching operation to be accomplished by the broach B within the said work W. At least two of the said pairs of broach holder jaws, one pair at each end of the machine, hold the broach B in broaching position at all times.

Assuming the work holders 16 fixed to the conveyor chains 15 travel from right to left during a broaching operation as indicated by the arrow A in FIG. 2, the 1st 2nd, 3rd and 4th pairs of broach holder jaws from the right in FIG. 1 are designated 21, 22, 23 and 24. The pairs of broach holder jaws 21 and 22 and the pairs of broach holder jaws 23 and 24 open sequentially to permit the work W carried by the work holders 16 to pass onto, along and off the broach B. At the same time, at least one of the pairs of broach holder jaws 21 and 22 and at least one of the pairs of broach holder jaws 23 and 24 simultaneously hold the broach B firmly in broaching position. In the particular embodiment of a continuous internal broaching machine illustrating the method steps of the invention disclosed in FIGS. l-ll inclusive, during continuous broaching operations one of the pairs of broach holder jaws 21 and 22 is always in engagement with one of the longitudinally spaced circular notches 25 in the lead end of the broach B to anchor the broach to accept the broaching tension, while one of the pairs of broach holder jaws 23 and 24 is always in engagement with the tail end of the broach B to hold the broach in broaching alignment.

The work holders 16 may be of any suitable shape and form to accommodate the receipt of work W placed thereinto as indicated at W in FIG. 1. In many instances, the work W need not be clamped in the work holder 16, and, in such cases, a suitable nest 19 is formed in the forward end of the upper narrow portion of the work holders 16 to accommodate placement of the work W therein. In the event the work W is not clamped in the work holder 16, after having been broached internally, it may drop from the work holders 16 onto a discharge chute 26 shown in FIG.'2. Of course, when required, the work W may be clamped in the work holder 16 by suitable manual or automatic clamping means, not shown.

In the continuous internal broaching machine 10 disclosed in FIGS. l-ll inclusive, each work holder 16 is preferably mounted on longitudinally adjacent link pins 27 of the conveyor chains 15 which preferably extend laterally through the base 28 of the said work holder 16 as best shown in FIG. 4. The base 28 of each work holder is preferably formed T-shaped adjacent the bottom thereof to provide pairs of slides 29 which ride on pairs of longitudinally disposed laterally spaced upper and lower ways 17 and 18 as the conveyor chain 15 is in motion. This or similar construction provides a firm support for the work holders 16 as they travel through the broach tunnel 20 under the operation of the chain conveyor 12. The upper narrow portion 160 of each work holder 16 is longitudinally chamfered for tunnel clearance, and is provided with a longitudinal bore 30 therethrough of a diameter to permit the work holder 16 to telescope freely over the broach B.

The work W to be broached is indicated to be cylindrical in shape, but may be of any shape, and is positioned in a nest or cradle 19 formed in each work holder 16 at the proper elevation so that the small lead end of the broach B can telescope freely into a pre-broaching bore 31 provided in the said work W. The longtiudinal center of the broach B when supported in two or more pairs of broach holder jaws 21, 22, 23 and 24 preferably is on or substantially on the longitudinal center of the work W and the longitudinal bore 30 through the work holder 16. This relationship, of course, would not obtain in instaces where the work W and/or the broaching cut therein are other than substantially symmetrical with respect'to each other. The proper set up of work holders and work to be broached on a continuous internal broaching machine of the invention would be obvious to anyone skilled in the art of broaching.

The sequential opening and closing of the pairs of broach holder jaws 21, 22, 23 and 24 to permit the conveyor 12 and work holders 16 mounted on the conveyor chains 15 to move the work W onto, along and off the broach B is accomplished in the embodiment of the invention disclosed in FIGS. 1-11 inclusive by a series of cams and allied elements operated by the movement of the work holders 16 along the ways 17. Each of the broach holder jaws of the pairs 21, 22, 23 and 24 thereof is preferably formed of a rectangular bar reciprocatingly fit into a transversely disposed rectangular broach holder jaw guide 32 formed through a side wall 33 of the broach tunnel 20. The said broach tunnel 20 is supported on the machine frame 11 and consists of two side walls 33 and a top 34 apertured at 35 to provide inspection access to each pair of broach holder jaws 21, 22, 23 and 24, The jaw guides 32 for each pair of broach holders are disposed transversely of the upper ways 17 and at such a distance thereabove as to permit the broach holder jaws 21, 22, 23 and 24 slidable therein to support and hold the broach .B in the desired position when moved into engagement therewith. At the bottom of each side wall 33 of the broach tunnel is a cam housing 36 formed to carry broach holder jaw operating cam means for each pair of broach holder jaws 21, 22, 23 and 24, the said broach holder jaw operating cam means being actuated by cam means carried by each work holder 16, all as hereinafter described in detail.

By reference to FIGS. 3 and 4 which show top and rear end views of a work holder 16, a pair of laterally extending fixed release cams extend laterally outwardly from the front portion of the said Work holder 16, and a pair of generally triangular relatively flat locking hammer earns 41 located somewhat rearwardly of and at an elevation above the release earns 40 are pivoted near their forward end to work holder 16 by means of vertically disposed hammer cam pivots 42 and extend laterally outwardly from the said work holder 16. Compression springs 43 in suitable lateral bores provided in the work holder 16 constantly urge the locking hammer cams 41 to swing outwardly about the hammer cam pivots 42 to their extended position as shown in FIG. 3. The said extended position of the locking hammer earns 41 is established by a nub 44 formed on the forward end of each locking hammer cam 41 which contacts the wall 37 at the upper relatively narrow portion 160 of the work holder 16. Each locking hammer cam 41 is provided with an angularly disposed cam surface 45, and is notched at its extreme outer end to provide a hammer head 46, the function of which will be later described.

FIGS. 57 inclusive discloses broach holder jaws operating cam means for each pair of broach holder jaws 21 and 22 at the lead end of the broach B, which jaws are actuated by the release cams 40 and the locking hammer cams 41 carried by the broach holders 16. The broach holder jaws 21 are shown in their closed position in FIGS. 5 and 6 engaging the broach B at the endmost circular notch 25 thereof while the broach holder jaws 22 are shown in their open position sufiiciently free of the broach B to permit the upper work holding portion 160 of a work holder 16 to pass therebetween, the said work holder 16 being indicated in FIG. 5 longitudinally between the pair of broach holder jaws 21 and the pair of broach holder jaws 22 shown therein.

Each broach holder jaw operating cam means consists of a set of sliding cams disposed in suitable chases and cam surfaces formed in a cam housing 36, one cam housing and one cam set being provided for each broach holder jaw of each pair of broach holder jaws 21 and 22 as best shown in FIGS. 5 and 6. Detailed description of the opening and closing of pairs of broach holder jaws by broach holder jaw operating cam means actuated by the fixed release cams 40 and the locking hammer cams 41 carried by the work holders 16 will be combined for clarity with the description of the operation thereof.

When the operator starts a continuous internal broaching mashing capable of carrying out the method steps of the invention disclosed in FIGS. 1-11 inclusive, it may be assumed that the pairs of broach holder jaws 21 and22 are closed and support and anchor the lead end of the broach B, and that the pairs of broach holder jaws 23 and 24 are also closed and support the tail end of the said broach B. As the upper flight of the chain 15 travels in a right to left or forward direction indicated by the arrow A in FIG. 2, the pair of broach holder jaws 21 are opened and closed by a work holder 16. The pair of broach holder jaws 22 are shown as opened by the same work holder 16 that had just closed the broach holder jaws 21. This is the attitude of the pairs of broach holder jaws 21 and 22 as shown in FIG. 5. The machine operator has placed work W in the nest or cradle 19 of the work holders 16 with an end face of the work W in abutment with the rear end wall of the cradle 19, and, in FIG. 5 a work holder 16 has telescoped the work W onto the lead end of the broach B and has moved the said work W to the shown position between the pairs of broach holder jaws 21 and the pair of broach holder jaws 22, the said work holder 16 having opened the broach holder jaws 22.

Each set of broach holder jaw operating cams 50 include a transverse jaw opening cam 51, a longitudinal cam 52, a broach holder jaw cam cut 53 on a broach holder jaw 21, 22, 23 or 24 forming cam surfaces 530 and 531 in the lower portion thereof, and a transverse jaw closing cam 54, all of said cams having complementary diagonal cam surfaces to provide rectilinear movement of a broach holder jaw 21, 22, 23 or 24 with respect to the travel of the work holder 16 carrying the release earns 40 and locking hammer cams 41.

With the broach holder jaws 21 closed and in engagement with the broach B as shown in FIG. 5, and assuming a work holder 16 is being moved along the upper ways 17, the release cam surface 400 of each of the fixed release cams 40 carried by the work holders 16 first contact the cam surface 510 of each of the transverse jaw opening cams 51 thereby moving the said jaw opening earns 51 laterally outwardly. This causes the cam surface 511 on each of the jaw opening cams 51 to travel along the cam surface 520 of each of the longitudinal cams 52 moving the said longitudinal cams 52 to the left as viewed in FIG. 5. The cam surface 521 of each of the longitudinal cams 52 come into sliding contact with the cam surface 530 formed on each of the broach holder jaws 21 at a cam cut 53 in the bottom thereof whereupon the broach holder jaws '21 move from their closed or advanced position shown in FIG. 5 to their open or retracted position similar to the open or retracted position of the broach holder jaws 22 also shown in FIG. 5; the broach holder jaws each having a like cam cut 53 and cam surface 530 therein.

After the broach holder jaws have been opened and moved to their retracted position as illustrated at the broach holder jaws 22 in FIG. 5, the upper work holding portion of the work holder 16 passes clear of the said broach holder jaws 22 and the cam surface 45 of each locking hammer cam 41 contacts the cam surface 540 of a transverse jaw closing cam 54 and moves the said jaw closing cams 54 laterally outwardly. Each jaw closing cam 54 also has a cam surface 541 which travels along the cam surface 522 on the longitudinal earns 52 moving the said longitudinal cams 52 to the right as viewed in FIG. 5. The cam surface 523 on each of the longitudinal earns 52 come into sliding contact with the cam surface 531 formed on each of the broach holder jaws 22 at the said cam cut 53 therein which moves the said broach holder jaws 22 from their open or retracted position shown in FIG. 5 to their closed or advanced position similar to that of the closed or advanced position of the broach holder jaws 21 also shown in FIG. 5; the broach holder jaws 21 each having a like cam surface 531 at the cam cut 53 therein.

The closing movement of each of the broach holder jaws 21 and 22 is stopped by a stop nut 47 threaded on a stop rod 48 extending laterally outwardly from the outer end of each broach holder jaw through a side plate cover 38 on the side wall 33 of the broaching tunnel 20 opposite each set of broach holder cams 50. A lock nut 49 is employed to maintain the stop nut 47 in its proper adjusted position. Thus, the stop nuts 47 prevent further movement of the broach holder jaws 22 at this time, the broach holder jaws 22 having moved to their advanced or closed position.

As the work holder 16 continues to move forward in its direction of travel after the broach holder jaws 22 are in their closed position, each locking hammer cam 41 is forced by the cam surface 540 of the jaw closing cam 54* in contact with the cam surface 45 of the said locking hammer cam 41 to pivot around its pivot 42 and compress the locking hammer cam spring 43 thereof. As the work holder 16 travels further, the outer flat edge 410 of the locking hammer cam 41 travels along the inner end face 542 .of the jaw closing cam 54 until it passes clear thereof whereupon the locking hammer cam 41 swings abruptly outwardly under the power of the retracted hammer cam spring 43, and the anvil surface 460 of the hammer head 46 of the locking hammer cam 41 strikes a sharp blow on the inner end face 542 of the jaw closing cam 54. Thusly, the broach holder jaws 22 are securely locked in their closed position like the closed position of the broach holder jaws 21 shown in FIG. 5.

Each of the pairs of broach holder jaws 21, 22, 23 and 24 are operated mechanically by cams carried by the Work holders hereinabove described for the opening of the broach holder jaws 21 and for the closing of the broach holder jaws 22. In the embodiment of the invention disclosed in FIGS. 1-11 inclusive, the pairs of broach holder jaws 23 and 24 are dimensioned so that they will engage the tail portion of the broach B. Inasmuch as the longitudinal thrust of the broach B is always taken by either one or both of the pairs of broach holder jaws 21 and 22, the tail portion of the broach B need not be provided with a circular notch 25 to provide an annular shoulder 25% for broach engagement longitudinally with the broach holder jaws when closed.

In FIGS. 9, 10 and 11, the broach holder jaws 21 and 23 are indicated in their closed position supporting the broach B. The broach holder jaws 22 and 24 are indicated in their open position. After a work holder 16 passes through the open broach holder jaws 22 at the lead end of the broach B and closes the same, a following work holder 16 opens the broach holder jaws 21 permitting work W to pass therethrough. Also, when a work holder 16 closes the open broach holder jaws 24 at the tail end of the broach B, the following work holder 16 will open the closed broach holder jaws 23 and permit work W to pass therethrough. The number of work holders 16 between the pairs of broach holder jaws 22 and 23 at any one time depends upon the spacing of the work holders 16 on the chain conveyor 12 and the longitudinal space between the said pairs of broach holder jaws 22 and 23. The space between the pairs of broach holder jaws 21 and 22 and between the pairs of broach holder jaws 23 and 24 is preferably in each instance sufiicient to permit the closing of the one pair of broach holder jaws while the other pair is opened. T husly, the broach B is always held by one of the pairs of broach holder jaws 21 and 22 and one of the pairs of broach holder jaws 23 and 24 as the work W is threaded on the leading end of the broach B and moved therealong the said broach B to cause a broaching operation to be performed thereon. At all times, the longitudinal tension of the broach B is taken by one pair of the broach holder jaws 21 or 22 at the lead end of the broach B while the tail end of the broach B is always held in its proper position by one of the broach holder jaws 23 or 24. The annular radially disposed shoulder 256 at each circular notch 25 in the broach B bears against the adjacent side of a pair of closed broach holder jaws 21 or 22 when closed to anchor the broach B against broach tension during the broaching operation of the embodiment of the continuous internal broaching machine disclosed in FIGS. 1-11 inclusive.

' Reference is now made to the embodiment of a broaching machine disclosing method steps of the invention shown in FIGS. 12-16 inclusive, which is like and similar to the broaching machine shown in FIGS. l-11 inclusive except that the 3rd and 4th pair of broach holder jaws designated by the reference numerals 6t and 61 respectively are each formed with a segmental frusto-conical cam surface 62 at the semi-circular notch 65 in the end thereof, which cam surfaces 62 engage complementary frustoconical annular cam surfaces 63 formed on the broach B-l at the tailmost end of circular notche 65 formed therein when the pairs of broach holder jaws and 61 are closed.

When the broach holder jaws 60 and 61 or both of the broach holder jaws 60 and 61 are closed, the closing force of the said broach holder jaws 64 and/ or 61 acting through the earns 62 and 63 urge the tail end of the broach 3-1 to the left as viewed in FIG. 14 placing tension thereon, at which time the lead end of the broach 13-1 is anchored at either or both of the 1st and 2nd pairs of broach holder jaws 21 and 22 with the annular radially disposed shoulder 254 at at least one of the circular notches 25 in the broach B-l bearing against the right hand face of at least one of the pairs of broach holder jaws 21 and 22. Thusly, as the pairs of broach holder jaws, 21, 22, 60 and 61 open and close sequentially responsive to the right to left movement of the work holders 16 through the broach tunnel 20, the broach B-l is maintained under tension at all times. Alternately, the broach holder jaws 60 and 61 may be substituted for broach holder jaws 21 and 22, and the broach formations 63 and 64 may be used at the lead end of the broach 13-1 of FIG. 14, all opposite hand to like construction employed at the tail end of said broach, thus also providing means for tensioning the broach.

The embodiment of a continuous internal breaching machine further illustrative of method steps of the invention is disclosed in FIGS. 17-21 inclusive, and is like and similar to the disclosure in FIGS. 1-11 inclusive, except that the 3rd and 4th pair of broach holder jaws designated by the reference numerals 76 and 71 and their operating mechanism is the same as for the pairs of broach holder jaws 21 and 22 of the disclosure in FIGS. 1-11 inclusive, and except that the entire broach holder jaws 7G and '71 and their operating mechanism is mounted on a generally rectangular slide 72 which is hydraulically urged rearwardly or to the left as viewed in FIGS. 17, 19 and 20 in respect to the 1st and 2nd pair of broachholder jaws 21 and 22, the latter being mounted through the walls of the broach tunnel 20 against longitudinal movement in respect thereto.

The slide 72 is indicated diagrammatically in FIG. 20 with the arrow A-72 indicating the unitary movement of the slide 72 and broach holder jaws and jaw operating mechanism thereon in respect to the broach holder jaws 20 and 21 to tension the broach 3-2. The broach B-Z differs from the broach B in that the broach B-2 is provided with circular notches 25 at both the lead end and at the tail end thereof to accommodate the broach holder jaws 21, 22, and 71 sequentially closed by the jaw operating mechanism hereinbefore described for the operation of the broach holder jaws 21, 22, 23 and 24 of the disclosure in FIGS. 1-11 inclusive.

In FIGS. 17, 18 and 19, the broach tunnel 20 is enlarged to accommodate therewithin longitudinal interior corner ways 73 within and on which the slide 72 is slidably mounted. The broach holder jaw operating mechanism for the broach holder jaws 7G and 71 carried by the slide 72 is the same as disclosed in FIGS. 1-11 inclusive, and has not been shown in FIGS. 17, 18 and 19 to avoid undue repetition. As in the machine disclosed in FIGS. 1-11 inclusive for carrying out the method steps of the invention, the jaw operating mechanism opens and closes the broach holder jaws 70 and 71 responsive to the movement of the Work holders 16 and the cams carried thereby.

The tunnel 20 is open at its top at 200 and is provided with an upturned bracket 202 onto which a hydraulic cylinder 74 having a piston 740 is mounted. The piston rod 741 extending from the piston 740 of the hydraulic cylinder 74 is connected to a bracket 720 extending upwardly from the slide 72. By applying hydraulic fluid under pressure by conventional means, not shown, to the hydraulic cylinder 74 on either one side or the other of the piston 740 thereof, the said slide 72 may be moved longitudinally of the ways 73 in either direction. Such means as a suitable threaded stop pin 75 and lock nut 76 may be employed to stop movement of the piston 746 of the hydraulic cylinder 74 whereby to locate accurately the position of the slide 72 and the pairs of broach holder jaws 76 and 71 mounted thereon in respect to the broach notches 25 before tensioning the 9 broach B-2. To observe the operation of the pairs of broach holder jaws 70 and 71 the top of the slide 72 is suitably apertured vertically at 721. The slide 72 is provided with a longitudinal tunnel 722 to accommodate the travel therethrough of the work holders 16.

The operation of the machine disclosed in FIGS. 17-21 inclusive employing method steps of the invention is the same as that of the operation of the machine illustrating the improved method disclosed in FIGS. 1-11 inclusive, except that when one of the pairs of broach holder jaws 21 and 22 and one of the pairs of broach holder jaws 70 and 71 are closed, as they always are during the operation of such an internal continuous broaching machine, and hydraulic fluid under pressure is applied to the right hand end of the hydraulic cylinder 74 as viewed in FIGS. 17 and 18, the slide 72 carrying the broach holder jaws 70 and 71 is moved and/or urged to the left as viewed in FIGS. 17 and 18 and shown diagrammatically in FIG. 20, thus applying tension on the broach B-2 between one of the pairs of broach holder jaws'21 and'22 and one of the pairs of broach holder jaws 70 and 71. This tensioning prevents broach sag between its lead end and tail end supports of the broach when the unsupported length of the broach is extremely great in proportion to its diameter.

By reference to FIGS. 22 and 23, the pair of broach holder jaws 70 and their operating mechanism is mounted on one generally rectangular slide 7200 and the pair of broach holder jaws 71 and their operating mechanism is mounted on a second rectangular slide 7201, rather than both pairs of broach holder jaws 70 and 71 being mounted on a single slide 72 as shown in FIGS. 17-21 inclusive. The use of two slides 7200 and 7201 each carrying one ofthe pairs of broach holder jaws 70 and 71 respectively is desirable when tensioning a broach B-2 of relatively large size and maintaining it under tension as the pairs of broach holder jaws 70 and 71 are alternately retracted and closed as hereinbefore described.

Each of the slides 7200 and 7201 are like and similar to the slide 72 shown in machine illustrating the method steps of the instant invention disclosed in FIGS. 17-21 inclusive, and the description thereof need not be repeated. The enlarged broach tunnel. 20 and the ways 73 are also similar to the construction thereof disclosed and described in connection with like elements shown in FIGS. 17-21 inclusive except that the enlarged broach tunnel 20 is longer and is provided with two upturned brackets 202 onto each of which a hydraulic cylinder 74 is mounted,-eachhydraulic cylinder being connected by its piston rod 740 to a bracket 720 extending upwardly from one of the slides 7200 and 7201.

In FIGS. 24, 25 and 26 is disclosed alternate constructionwherein hydraulic means are provided rather than mechanical means for retracting and closing the pairs of broach holder jaws hereinbefore described for sequentially holding the broach in positionas a work holder carries the. work thereby. The hydraulic means will ,be described as that for retracting and closing the 1st pair of broach'holder jaws designated by the reference numeral 21. It is obvious that the same hydraulic means may be employed for. retracting and closing the 2nd, 3rd and 4th pairs of broach holder jaws in the several embodi mentsof the invention disclosed herein.

FIG. 26 is afragmentary side elevational view of the broach tunnel 20 at the lead end of a continuous internal broaching machine 100 similar to the broaching machine disclosed in FIGS.-1-11 inclusive except that the pairs of broach holder jaws 21 are hydraulically operated, the said FIG. 26 serving as a locator view indicating where FIGS. 24 and 25 have been taken.

Referring now particularly to FIGS. 24 and 25, a hydraulic cylinder 80 is mounted on the outer side of the broach tunnel 20 opposite the laterally outer end of each broach holder jaw 21. Each hydraulic cylinder 80 has a piston 81 and a piston rod 82, the latter being suitably ,through.

anchored by such means as a threaded connection 820 to a broach holder jaw 21. Movement of the pistons 81 closes and retracts the pair of broach holder jaws 21 into and out of engagement with the broach B at the circular notch 25 therein.

As hereinbefore described in connection with the particular machine disclosed in FIGS. 1-11 inclusive to illustrate the method steps of the invention, work W carried by cradle 19 in the upper portion 160 of work holders 16 is telescoped over and broached by the broach B as the continuous conveyor chains 15 move work holders 16 along the longitudinal upper ways 17. The work holders 86, one of which is shown in FIGS. 24 and 25, are like and similar to the broach holders 16 except they carry only one cam bar 83 fixed to one side thereof which shifts a hydraulic valve 84 which, through a conventional type of hydraulic circuit, not shown, applies hydraulic fluid under pressure to the hydraulic cylinders to close the pair of broach holder jaws 21 when the cam bar 83 operates the hydraulic valve 84 through a suitable push rod 85. After the cam bar 83 passes the push rod 85 it moves outwardly to the limit of its movement governed by a shoulder 850 thereon which comes to rest against a push rod mounting block 851 secured to the broaching machine frame 11. The said push rod 85 may be either spring loaded or hydraulically urged to its outwardly extended position ready for contact by a cam bar 83 fixed on successive passing work holders 86 carried by the continuous chains 15. The length of the cam bar 83 carried by each Work holder 86 determines the timing of the retracting and closing of the broach holder jaws 21as each successive work holder 86 approaches and passes there- In the embodiment of the broaching machine disclosed in FIGS. 12-16 inclusive further illustrating broaching steps of the invention, the pairs of broach holder jaws 21, 22, 60 and 61 employ the same construction as just described if hydraulically powered rather than mechanically operated.

However, in the disclosure in FIGS. 17-21 inclusive and the alternate construction disclosed in FIGS. 22 and 23 wherein pairs'of broach holder jaws 21, 22, 70 and 71 are employed, and the pairs of broach holder jaws 70 and 71 are mounted on a single common slide 72, or, the broach holder jaws 70 may be mounted on one slide 7200 and the broach holder jaws 71 may be mounted on a second slide 7201, it is obvious that other means as just described may be used for hydraulically powering the pairs of broach holder jaws 70 and 71, except that the hydraulic cylinders 80 and hydraulic valves 84 for powering the pairs of broach holder jaws 70 and 71 must be mounted on the single common slide 72, or, if employed on the two separate slides 7200 and 7201 respectively. In the method of continuous internal broaching incorporating the invention, the work W having a broaching aperture therethrough is carried by work holders traveling in a given path for being telescoped over a broach supported at spaced locations at both the lead end and at the tail end of the broach, each support being retracted and advanced in timed relationship with respect to the movement of the work and work holders to admit of the work passing along said broach without interference from the broach supports, at least one of the broach supports at each end of the broach is supporting the said broach at all times, and, the said one of the broach supports at the lead end of the broach anchoring said broach against longitudinal movement in the direction of the travel of the work W simultaneously with supporting the said lead end of the broach. The method includes that the broach may be tensioned while the foregoing is accomplished.

Although but several illustrative embodiments of how the method of continuous internal broaching of the invention may be carried out have been disclosed herein, it is obvious that many different means may be employed to carry out the method of the invention and that many modifications may be made in the method steps of the invention, all without departing from the spirit and scope of the invention as defined by the appended claim.

We claim:

1. A method of internal broaching wherein Work apertured for telescoping onto the lead end of a broach is moved continuously in longitudinal spaced relationship along a given path,

supporting said broach in alignment with said given path and the aperture in said work at two spaced places at each of the lead and tail ends of said broach,

a sequentially withdrawing and replacing each said support as said work passes the same permitting uninterrupted movement of said work along said broach to broach the same,

and anchoring said broach at all times against longitudinal movement at one or the other of the broach supports at the lead end of said broach while supporting said broach at one or the other of the broach supports at the tail end of said broach;

2. A method of internal bro-aching wherein work apertured for telescoping onto the lead end of a branch is moved in longitudinal spaced relationship along a given path,

supporting said broach in alignment with said given path and the aperture in said work at two spaced places at each of the lead and tail ends of said broach,

sequentially withdrawing and replacing each said support as said Work passes the same permitting uninterrupted movement of said work along said broach to broach the same,

and anchoring said broach at all times at one or the other of the broach supports at the lead end of said Ibroach against longitudinal movement in the direction of the movement of the work while supporting said broach at one or the other of the broach supports at the tail end of said broach.

3. In a method of internal broaching wherein work provided with a broaching aperture therethrough for telescoping onto the lead end of a broach is carried in longitudinally spaced broach holders moving continuously along a given path,

supporting the breach at two spaced places at each of the lead and tail ends thereof in alignment with said broaching aperture and said give-n path to telescopingly receive said .apertured work on its lead end,

sequentially withdrawing and replacing each said support as said work and workholder passes the same,

anchoring said broach at all times against longitudinal movement at one :or the other of the bmoach supports at the lead end of said broach while supporting said broach at one or the other of the broach supports and the tail end of said broach,

and applying tension on said broach at all times between at least one of the lead end supports and at least one of the tail end supports.

'4. In a method of internal broaching wherein work provided with a broaching aperture therethrough for telescoping onto the lead end of a broach is carried in longitudinally spaced broach holders moving continuously along a given path,

supporting the broach at two spaced places at each of the lead and tail ends thereof in align-ment with said broaching aperture and said given path to telescopingly receive said apertured work on its lead end,

sequentially withdrawing and replacing each said support as said work and workholder passes the same,

anchoring said broach at all times against longitudinal movement at one or the other of the broach supports at the lead end of said broach,

and applying tension on said broach at the tail end thereof while supporting said broach at one or the other of the broach supports and the said tail end of said broach.

5. A method of internal broaching wherein work apertured for telescoping onto the lead end of a broach is moved in longitudinal spaced relationship along a given path,

supporting said broach in alignment with said given path and the aperture in said Work at two spaced places at each of the lead and tail ends of said broach,

sequentially withdrawing and replacing each support as said work passes the same permitting uninterrupted movement of said work along said broach to broach the same,

anchoring said broach at all times against longitudinal movement at one or the other of the broach supports at the lead end of said broach,

and applying tension at all times to said broach at one or the other of the broach supports at the tail end of said broach.

"6. A method of internal broaching wherein work apertured for telescoping onto the lead end of a broach is moved in longitudinal spaced relationship along a given path,

power gripping and supporting said broach in alignment with said given path and the aperture in said work at two spaced places at each of the lead and tail ends of said broach,

sequentially withdrawing and replacing each support as said work passes the same permitting uninterrupted movement of said work along said broach to broach the same,

anchoring said broach at all times against longitudinal movement at one or the other of the broach supports at the lead end of said broach,

and applying tension at all times to said broach responsive to the power gripping and supporting the same at one or the other of the broach supports at the tail end of said broach. 7. A method of internal broaching wherein work apertured for telescoping onto the lead end of a broach is moved in longitudinal spaced relationship along a given path,

power gripping and supporting said broach in alignment with said given path and the aperture in said work at two spaced places at each of the lead and tail ends of said broach, sequentially withdrawing and replacing each support as said work passes the same permitting uninterrupted movement of said work along said broach to broach the same,

anchoring said broach at all times against longitudinal movement at one or the other of the broach supports at the lead end of said broach,

and applying tension at all times to said broach responsive to the power gripping and supporting the same at one or the other of the broach supports at one of the lead and tail ends of said broach.

No references cited.

WILLIAM W. DYER, JR., Primary Examiner. G. A. DOST, Assistant Examiner. 

1. A METHOD OF INTERNAL BROACHING WHEREIN WORK APERTURED FOR TELESCOPING ONTO THE LEAD END OF A BROACH IS MOVED CONTINUOUSLY IN LONGITUDINAL SPACED RELATIONSHIP ALONG A GIVEN PATH, SUPPORTING SAID BROACH IN ALIGNMENT WITH SAID GIVEN PATH AND THE APERTURE IN SAID WORK AT TWO SPACED PLACES AT EACH OF THE LEAD AND TAIL ENDS OF SAID BROACH, A SEQUENTIALLY WITHDRAWING AND REPLACING EACH SAID SUPPORT AS SAID WORK PASSES THE SAME PERMITTING UNINTERRUPTED MOVEMENT OF SAID WORK ALONG SAID BROACH TO BROACH THE SAME, AND ANCHORING SAID BROACH AT ALL TIMES AGAINST LONGITUDINAL MOVEMENT AT ONE OR THE OTHER OF THE BOACH SUPPORTS AT THE LEAD END OF SAID BROACH WHILE SUPPORTING SAID BROACH AT ONE OR THE OTHER OF THE BROACH SUPPORTS AT THE TAIL END OF SAID BROACH. 